Access a file from document media in Liferay

If the requirements to access files from document media and do some operaions on that file ,then the below code snippet will help us.

long folderId = 0;
try {
ThemeDisplay themeDisplay = (ThemeDisplay) request
.getAttribute(WebKeys.THEME_DISPLAY);
ServiceContext serviceContext = new ServiceContext();
serviceContext.setScopeGroupId(themeDisplay.getScopeGroupId());
List<DLFolder> groupFolder = DLFolderLocalServiceUtil.getFolders(
themeDisplay.getScopeGroupId(),
DLFolderConstants.DEFAULT_PARENT_FOLDER_ID);
boolean IsFolderExits = false;
if (groupFolder.size() > 0) {
for (DLFolder folders : groupFolder) {
                              //To get particalar folderId
      if ("FolderName".equalsIgnoreCase(folders
.getName().trim())) {
folderId = folders.getFolderId();
IsFolderExits = true;
break;
}

}
}

                  String file = null;
List<DLFileEntry> fileEntries = null;
if (Validator.isNotNull(folderId)) {

try {
                              //To get the List of files exits in that particular folder
fileEntries = DLFileEntryLocalServiceUtil.getFileEntries(
themeDisplay.getScopeGroupId(), Long.valueOf(folderId));

} catch (NumberFormatException e) {
e.printStackTrace();
} catch (SystemException e) {
e.printStackTrace();
}
if (fileEntries.size() > 0) {

for (DLFileEntry entries : fileEntries) {
                                   //This will provide us to get the complete file Location of document Media
file = PropsUtil.get("dl.hook.file.system.root.dir") + "/"
+ entries.getCompanyId() + "/"
+ entries.getFolderId() + "/" + entries.getName()
+ "/" + entries.getVersion();
}
}
}


} catch (SystemException e) {
e.printStackTrace();
} catch (PortalException e) {
e.printStackTrace();
}